Perspective-determining instrument.



I WITNESSE I E. M. ANDERSON. PERSPECTIVE DETERMINING INSTRUMENT. APPLICATION FILED mu! 3. 1916.

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'that two EMMA M. ANDERSON, OF BOONE, COLORADO.

PERSPECTIVE-DETERMINING INSTRUMENT.

Specification of Letters Patent.

Patented Mar. 13, 1917.

Application filed July 3, 1916. Serial No. 107,350.

To all whom it may concern:

Be it known that I, EMMA M. ANDER- son, a citizen of the United States, resid ing at Boone, county of Pueblo, and State of Colorado, have invented certain new and useful Improvements in Perspective- Determining Instruments, of which the following is a specification.

This invention relates to perspective detel-mining instruments.

My object is to provide an instrument of improved construction for determining the exact slant of the receding edges in a perspective drawing made directly from the object which will be adapted for such sin ple adjustments and so clearly demonstrate its principles that a theoretical knowledge of perspective is unnecessary to its proper use by pupils under the direction of the drawing supervisor.

My invention is based upon the principle adjustable perspective strips pivoted to a handle, will, when the handle is vertical, register in the vertical plane the apparent slant of the receding horizontal edges of an object, and in that type of perspective determining instrument I provide improvements whereby, after the strips have first been adjusted, independently of each other, the instrument may be used for making a perspective drawing. Further improvements consist in a series of dots, as distinguished from lines or graduations, on the perspective strips, and means adjustable lengthwise of the strips adapted for determining the relative foreshortening of the faces of an object as they appear in perspective. More particularly, this latterly mentioned part of the invention contemplates members which are slidable on the perspective strips and pivoted needles carried by said members which are adapted to be brought into visual register with the vertical edges of the object and to indicate on the series of dots the positions thereof. The dots, as distinguished from lines, have the advantage of always remaining in the same relation, regardless of the angularity of adjustment of the perspective strips; prevent confusion in the observation; and insure clearness and precision, as

will appear more fully hereinafter.

While the preferred embodiment of my invention is set forth hereinafter and appears in the accompanyingrdrawings, such disclosure is to be considered as illustrative, rather than restrict've, of-the scope of the invention, as I am aware that modificatime could be resorted to without departing from the essential principles of the invention.

In the accompanying drawings:

Figure 1 isa front elevation of the invention it might appear when held in vertical position and adjusted for a given observation; and v Fig. 2 is a similar view showing the manner in which the invention is used.

To the flat metal handle H, arms A and L are pivoted at E and T, respectively, on opposite sides of said handle so that they may be independently revolved about their pivots. The pivot E is disposed about one half inch from the upper end of the handle H, and the pivot T close to the upper end of the handle. The pivotal connections E and T may be of any frictional type which will insure the retention of the strips or arms A and L where positioned. Washers F and N may be used with the pivots to aiford the requisite frictional contact.

The strips or arms A, L, bear a series of dots at equal intervals, running along-the longitudinal median lines thereof and originating at the respective pivotal connections E, T. Numbers are provided in connection with the rows of dots, thus providing scales for measuring the foreshortening of surfaces and for comparing the appearance of the width of faces of an object seen in perspective.

Slidable on the arms A, L, are bands Y which frictionally engage the edges or the edges and faces of the said arms or strips so that said bands are adapted to retain themselves where set.

Pivoted at X to the respective adjustable bands Y are fiat needles Z which may be swung to any desired angularity in relation to the strips A, L. The pivots X are in line with the dots forming the scales on the respective strips.

The principle involved in my invention is that by proper adjustment,the perspective strips register in a vertical plane, the apparent slat of the receding horizontal edges of the object under observation. It is important, therefore, that the handle H be held in a vertical position while the strips A and L are being adjusted; also when the appearance of the receding lines is being recorded on the drawing. The observer may ascertain whether he is maintaining the same position throughout his observation by testing a line already recorded on the drawing and if thetest shows a deviation from the line already drawn, the position of the observer should @be corrected accordingly. In making observations, either the upper orjthe lower edges of the perspective strips will be sighted over according to whether the object is below or above the level of the eye. 7 E

Referring to Fig. 2, the instrument is used in the following manner: First, draw the nearest vertical edge of the object on a sheet. The handle H is held vertically and is covering the nearest vertical edge of the object. The arms A, L, are then adjusted to such po tions that the upper edges of said arms appear to coincide with the edges A, L, respectivelyn The device may then be placed upon the sheet, the appearance of the receding lines oorresponding to the edges A, L, being en properly related to the nearest vertical edge previously drawn and the edges of the strips A, L, will be used for drawing, with a suitable pencil or other marking device, lines corresponding-to the edges A, L of the objo t.

Next adjust the strip-s A, L, to register with the edges A L and record these lines on the sheet, as before; then proceed in like manner to determine and record the edges A L v The next consideration should be the length A L on the drawing. To determine these lengths, the bands Y should be slid along the strips A, L, until the needles Z appear to visually coincide with the vertical edges Z of the object. The relative lengths of A and L having been established, a comparison should be made between the height of the nearest vertical edge of the object and the apparent lengths of the edges A L that these three dimensions may appear in the drawing under proper relative proportions. Other lines that should appear in the drawing should determined in a manner similar to the procedure previously set forth and the drawing may then be completed.

The use of the series of dots for the scales on the strips A, L, in connection with the needles Z, have a distinct advantage over lines of graduations, because the dots always remain; in the same relation, regardless of the adjustment of the strips A and L, whereas vertical graduations would appear to on a slant when the arms A and L were placed in position for use and would thus tend to give a confused idea, rather than.

clearness and. precision, when making the observation.

My invention may be advantageously used by any draftsman, but it finds peculiar utility in teaching children how to make per spective drawings and indemonstrating'the .theory of perspective. Particularly in. the school room where there are a relatively large number of pupils arranged in stationary seats and viewing the object from dif ferent positions, the simplieity of adjust ;ment, ease of explanation and clearness of ,principle involved, adapt the device to more gready use under these conditions than any jother perspective determining instrument of which I have knowledge. 21

Having thus described my invention, what I claim as new and desire to secure by Let ters Patent, is

1. instrument for determining perspective, comprising a handle, a perspective strip pivoted thereto, a member movable along the strip, and a needle pivoted to the member. s

2. An instrument for determining perspective, comprising a handle, a perspective strip pivoted thereto which is provided with a scale having dots representing the divisions thereof, a member movable along the strip, and a needle pivoted'to the member.

3. An instrument for determinino perspective, comprising a handle, perspective strips independently pivoted to the handle and adapted for independent adjustment, each strip having a scale provided with dots representing the divisions thereof, members movable .along the respective perspective strips, and needles pivoted to the members, said perspective strips being adapted for adjustment for the purpose of recording the appearance of the receding lines of an object seen in perspective and to be used in connection with the laying oil of the lines of a perspective drawing, said needles being adapted to determine the relative foreshortening of the faces of an object as they appear in perspective.

In'testimony whereof, I hereunto aflix my signature.

EMMA M. ANDERSON Copies of this patent may be obtained for five'cents each, by addressing the fiommissioner of Patents, Washington, I). 0. 

